Examples of footwear suitable for outdoor use over adverse terrain such as snow, ice, mud, rocks, etc., are well known. Accessory devices for such footwear are also known. Hobnails, screws and studs are examples of such accessory devices. Each of these accessory devices include significant limitations of use. Hobnails have been inserted into the soles of shoes or boots to prevent wear and improve traction. Hobnails are typically short nails which tend to quickly wear on rock surfaces and are often inadvertently removed during use in mud, moss, rocks and ice. Metal screws have also been used to improve traction in footwear. In a typical application, one or more metal screws are secured into a shoe sole. Metal screws typically wear relatively quickly and, once worn, tend to slide on surfaces leading to a decrease in traction across certain flat surfaces such as concrete floors, etc. Other examples of footwear suitable for outdoor use in water and rocks include felt and treaded rubber soles.
Tire studs, which may include carbide or porcelain studs, have been used to improve the traction of vehicles. In a typical application, a single generally cylindrical carbide element is secured within an aluminum housing. Porcelain studs are relatively brittle and may be damaged by ground impact. One limitation of tires studs is the propensity of the carbide or porcelain stud element to round over. In certain applications, the rounded-over element may lead to a decrease in traction, such as on concrete floors or other flat surfaces.
U.S. Pat. No. 5,897,177 to Bergstrom discloses a stud having a multifaceted surface for use on a tread element. The stud includes a body portion including a head and an elongated shank portion extending from the head. A mound of shard-like particles of a hard and durable material is bound together on and to the head of the stud such that the mound of particles has a multifaceted surface including multiple points which can engage the terrain. One limitation of the studs according to Bergstrom is the tendency of the particles to fracture during use due to the relatively few contact points defined by the sharp edges of the particles. The carbide fractures are typically uncontrolled and relatively large portions of the particles may be shed during a fracture. Because of the tendency of shedding relatively large particle portions, Bergstrom's device is believed to wear relatively quickly leading to poor economy of use. Additionally, the sharp edges of these studs may have a tendency to catch or snag on certain surfaces, such as carpet, which may lead to a tripping hazard. Furthermore, the relatively few contact points result in high contact forces which may be damaging to certain floors, such as wood and tile floors.
Accordingly, despite the attempts to develop improved devices for improving traction on adverse surfaces, there remains a need for an improved stud-style carbide traction device.